As a film formation method, for example, there has been known a method for forming a film by supplying a film-forming ink obtained by dissolving a film-forming material in a solvent onto a base material using a liquid droplet ejection method, and removing the solvent from the film-forming ink on the base material (see, for example, PTL 1).
It has been proposed that by using this film formation method, for example, an organic layer (for example, a light-emitting layer, a hole transport layer, etc.) of an organic electroluminescence (organic EL) element, a colored layer of a color filter, a conductor pattern of a wiring board, etc. are formed.
Patterning (film formation method) of such an organic layer or a film of a conductor pattern or the like is performed by forming a partition wall (bank) including a concave part corresponding to the shape of a film to be formed to ensure a film-forming region, and then, supplying a film-forming ink into the opening part, and thereafter removing a solvent.
In a film formation method for a film having such a configuration, a film-forming ink (liquid droplet) is supplied into an opening part according to the volume of the opening part surrounded by a partition wall, that is, within such a range that the film-forming ink does not overflow from the opening part.
Here, for example, in the organic EL element, pixel miniaturization has progressed due to the recent demand for high definition, and as a result, accompanying the miniaturization of the volume of the opening part, a solid amount necessary for forming a film is required to be obtained with a small number of liquid droplets.
As a method of solving such a problem, for example, a method of increasing the concentration of a film-forming material (a solute) contained in the film-forming ink is conceivable.
However, this method has a problem that depending on the type of the film-forming material, the concentration thereof cannot be increased due to the limit on the solubility thereof, or the viscosity of the film-forming ink increases as the concentration thereof increases, which causes ejection failure when the film-forming ink is ejected by a liquid droplet ejection method, and so on.